I recommend testing for possible edge cases as well, for example, what happens if the array is empty, or if there are duplicate values? What if some values are missing? Other than that, I think it's ready.

Same here. I'm hoping this is a test error.

I would even go a step further with refactoring the name of the method and call it 'santa_clausable?'.

Great job!

Just a couple of things, style-wise, that I can see: the return statement isn't required (it'll still output the string), and you can use single quotes for the string as well. The only time you really need double-quotes is if you need to do string interpolation or if there's going to be apostrophes and/or single-quotes in your string.